Uniform dispersion of pre-synthesized nanotubes in metal matrices is difficult to achieve, and there is substantial damage to the nanotubes during subsequent composite fabrication. The demonstration of an in-situ process involving chemical vapor deposition of single-wall and multi-wall carbon nanotubes into iron matrices without the concomitant formation of iron carbides is reported here. It wa...

density-functional theory is used to investigate sulfur dioxide physisorption inside and outside of single-wall carbon nanotube of (5,0) and (5,5). this study is conducted at b3lyp/6-31g* level of theory. sulfur dioxide molecule is studied with axis oriented parallel or perpendicular to the nanotube wall. both internal and external adsorption on nanotubes is increased with the angle of interact...

Unusual physical properties of single-wall carbon nanotubes have started a search for similar tubular structures of other elements. In this paper, we present a theoretical analysis of single-wall nanotubes of silicon and group-III-V compounds. Starting from precursor graphenelike structures we investigated the stability, energetics, and electronic structure of zigzag and armchair tubes using th...

We report in situ environmental transmission electron microscope observations of the nucleation and growth of multi-wall and single-wall carbon nanotubes formed by the catalytic decomposition of acetylene (C2H2) on Ni/SiO2 catalyst. The growth rate, structure and morphology of the carbon nanotubes formed depended upon reaction temperature and pressure. Under 20-100 mTorr of gas pressures at 480...

the effective parameters of (5, 0) and (5, 5) single-wall carbon nanotubes during the interaction with carbon dioxide as sensors are determined. the interaction of carbon dioxide  molecules with internal and external walls of the nanotubes is studied using gaussian 03 coding by density functional theory (dft) at the b3lyp/6-311g level of theory. co2 rotation around tube axles vertically and par...

We fabricated field-effect transistors based on individual singleand multi-wall carbon nanotubes and analyzed their performance. Transport through the nanotubes is dominated by holes and, at room temperature, it appears to be diffusive rather than ballistic. By varying the gate voltage, we successfully modulated the conductance of a single-wall device by more than 5 orders of magnitude. Multi-w...

We have measured a strictly linear pi plasmon dispersion along the axis of individualized single-wall carbon nanotubes, which is completely different from plasmon dispersions of graphite or bundled single-wall carbon nanotubes. Comparative ab initio studies on graphene-based systems allow us to reproduce the different dispersions. This suggests that individualized nanotubes provide viable exper...

A bstract. Detailed growth mechanism of single-wall nanotube bundles and of multiwall nanotubes of carbon is investigated using ab initio and parametrized calculations. Our results show that single-wall tubes grow only in presence of a catalyst, whereas multi-wall tubes, stabilized at the growing edge by a covalent "lip-lip" interaction, may form in a pure carbon atmosphere. The individual tube...

Based on Timoshenko laminated beam models, this paper investigates the influence of initial stress on the vibration and transverse wave propagation in individual multi-wall carbon nanotubes (MWNTs) under ultrahigh frequency (above 1 THz), in which the initial stress in the MWNTs can occur due to thermal or lattice mismatch between different materials. Considering van der Waals force interaction...

Density-functional theory is used to investigate sulfur dioxide physisorption inside and outside of single-wall carbon nanotube of (5,0) and (5,5). This study is conducted at B3LYP/6-31G* level of theory. Sulfur dioxide molecule is studied with axis oriented parallel or perpendicular to the nanotube wall. Both internal and external adsorption on nanotubes is increased with the angle of interact...